Microfocus X-ray inspection, fluorescent penetrant inspection and visual inspection are conventional, non-destructive evaluation techniques used on metal components before the component is mounted in a gas turbine engine. These techniques reveal flaws or cracks in the metal that would result in the component failing during its operating life. Thus, the component can be rejected before it is mounted in the engine. For a number of reasons, these techniques have not been very reliable when used on ceramic components. First, a ceramic component may have hidden cracks or flaws that are related to a weakness in the ceramic, but which cannot be detected due to resolution limitations of these techniques. Second, these techniques may detect flaws or cracks in the ceramic that are not indicative of weakness in relation to the anticipated operational stress for the part, resulting in the rejection of a perfectly good part.
Accordingly, there is a need for a non-destructive evaluation method for ceramic components that only detects flaws or cracks in the ceramic indicative of a weakness in relation to the anticipated operational stress that the material will be exposed to during engine operation.